Improvements in or relating to radar systems

(19)

(11)

EP 0 474 977 A3

(12)	EUROPEAN PATENT APPLICATION

(88)	Date of publication A3:
	13.01.1993 Bulletin 1993/02

(43)	Date of publication A2:
	18.03.1992 Bulletin 1992/12

(21)	Application number: 91109222.9

(22)	Date of filing: 06.06.1991

(51)	International Patent Classification (IPC)⁵: H01Q 21/22, H01Q 3/26, G01S 7/28

(84)	Designated Contracting States:
	DE ES FR IT

(30)

Priority:

25.08.1990 GB 9018714

(71)	Applicant: Siemens Plessey Electronic Systems Limited
	Chessington, Surrey KT9 1QZ (GB)

(72)	Inventor:
	Young, Roger Cowes, Isle of Wight, P031 7PP (GB)

(74)	Representative: Fish, Norman Ernest
	Siemens Group Services Limited, Intellectual Property Department, Roke Manor, Old Salisbury Lane Romsey, Hampshire SO51 0ZN Romsey, Hampshire SO51 0ZN (GB)

(56)

References cited: :

(54)	Improvements in or relating to radar systems

(57) In radar apparatus where an antenna comprises a phased planar array of radiator elements operative to provide a steerable beam, the suppression of sidelobes can be effected by phase weighting.
The apparatus of the invention comprises a planar array of radiator elements, in which the elements of the said array are operatively associated with beam steering means, the said array being defined by a plurality of groups of elements, each group having n elements, the beam steering means comprising a beam forming network, and n sub-array phase controllers one for each of n sub-arrays wherein each sub-array is defined by one element selected randomly from each group, the sub-array phase controllers each being effective to control the phase of signals radiated by a sub-array with which it is operatively associated. This enables the phase of signals from one or more sub-arrays to be phase offset and thus provide a phase weighting effective for good sidelobe suppression.

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